Containers: More on Volumes

In my last post I showed how you can create a volume with your container. I then showed a few things you can with a container using a volume. I want to explore volumes just a little bit more.

Locate Your Volume

To have a little more fun with volumes, first, let’s share a drive. You do this in the Settings in Docker Desktop (assuming that’s what you’re using):

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While this should just work, it didn’t for me until I restarted Docker. So you may need to do that. Go to the drive and create a directory. I’m putting one in at C:\Docker\SQL.

Once I’ve done that, let’s create a new container:

docker run `
--name SQL19 `
-p 1433:1433 `
-e "ACCEPT_EULA=Y" `
-e 'SA_PASSWORD=$cthulhu1988' `
-v C:\Docker\SQL:/sql `
-d mcr.microsoft.com/mssql/server:2019-CTP2.5-ubuntu

Note, I’m using C:\Docker\SQL in the -v volume command and I’m telling it to map to /sql in my container.

Now, things get really fun. I’m going to add another folder: C:\Docker\sql\bu. In that folder, I’m going to add a file: AdventureWorks2017.bak.

Let’s connect up to our container directly. Use this command:

docker exec -it SQL19 "bash"

That will launch a bash shell inside the Linux container. There, I can list the files using the ‘ls’ command and it looks like this:

Notice the sql folder listed there. I can cd to that and I’ll see the bu folder. Changing to that directory and calling for a list, I’ll see my AdventureWorks2017.bak file.

Yes, I moved a file into a container by just copying it there. Yes, I could then run a restore from that backup.

Conclusion

Easily adding and controlling files this way adds to what we can do with containers. These things are going to become a major part of all my development and testing going forward. I’ll still be using VMs and all the rest of the stuff I have available. This is just another tool in the toolbox.

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